Lesson 4.5.1.6

4.5.1.6 Ordinal numbers, counting and measurement Quiz: AQA Computer Science, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.5.1.6, Ordinal numbers, counting and measurement: 20 multiple choice questions for the AQA Computer Science (7517), Unit 5: Fundamentals of data representation, written with Revision Ninja.

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The 20 questions

  1. What are ordinal numbers used for?

    • Describing the position of an object in a well-ordered set
    • Measuring the size of a quantity on a continuous scale
    • Representing the value of a single binary digit
    • Counting the total number of items in a collection

  2. In the well-ordered set S = {'a', 'b', 'c', 'd'}, which object is the 3rd?

    • 'd'
    • 'b'
    • 'a'
    • 'c'

  3. Which kind of number is used for measurements such as mass or temperature?

    • Real numbers
    • Ordinal positions only
    • Natural numbers
    • Positive integers only

  4. What does an ordinal number tell you about an object?

    • The base in which the object is written
    • Its position in an ordered sequence, such as 1st or 2nd
    • How many objects are in the whole collection
    • The exact real length of the object

  5. Which set of numbers is most appropriate for counting the number of students in a class?

    • The natural numbers
    • The irrational numbers
    • The negative integers
    • The real numbers with decimal places

  6. Which of these is a measurement rather than a count?

    • The number of apples in a basket
    • The position of an apple in a queue
    • The number of apples sold in a day
    • The mass of an apple, recorded as 0.12 kg

  7. What does measurement generally produce?

    • Only ordinal positions in an ordered list
    • Values that may be real and fractional, such as 2.75
    • Only whole numbers, since instruments always round down
    • Only negative integers when a scale is zeroed

  8. A tank holds 2.75 litres. Which set of numbers is needed to represent this measurement exactly?

    • Real numbers, since 2.75 has a fractional part
    • Natural numbers, because all measurements round to whole numbers
    • Natural numbers, because 2.75 is a count of litres
    • Integers only, because litres are never fractions

  9. In a race, Priya finishes 5th. What does '5th' represent?

    • The number of laps she completed
    • The number of runners who finished the race
    • Her position in the ordered finishing list
    • The time she took, in seconds

  10. A digital scale reads 0.350 kg. Which description of this value is correct?

    • An ordinal position in a list of weights
    • A real number, since it has a fractional part
    • A natural number, since it counts grams
    • A negative integer, since mass is removed from the scale

  11. Which situation uses an ordinal number?

    • The length of a pencil, measured as 17.5 cm
    • The temperature of water, recorded as 21.3 C
    • The third athlete to cross the finish line
    • The total of 45 votes cast in an election

  12. In the ordered list of years 1990, 1991, 1992, which year is in 2nd position?

    • 1993
    • 1991
    • 1990
    • 1992

  13. A sensor records an altitude of 1,350 m. From which set of numbers is this value drawn?

    • The ordinal numbers
    • The irrational numbers only
    • The natural numbers only
    • The real numbers

  14. How many empty seats can a room have, and which set of numbers describes that count?

    • Only one seat, described by the ordinal numbers
    • Zero or more, described by the negative integers
    • Zero or more, described by the natural numbers including zero
    • Any real value, described by the irrational numbers

  15. A thermometer reads -3.5 C. Which set describes this value?

    • The natural numbers, since temperatures are counted
    • The real numbers, since it is negative and has a fractional part
    • The ordinal numbers, since it gives a position
    • The irrational numbers, since temperatures are never rational

  16. A sensor counts events as natural numbers but reports averages as real numbers. Which justification is best?

    • Averages are ordinal numbers because they place the individual values in a fixed order
    • Averages are always natural numbers that are rounded down to the nearest whole value
    • Counts must be real numbers so that they can be added directly to any averages
    • Counts are whole and non-negative, while averages can take any real value including fractions

  17. Which argument shows that the natural numbers are a subset of the real numbers?

    • Real and natural numbers contain the same number of values in every interval on the number line
    • Every real number is a natural number once it has been rounded to the nearest whole value
    • Natural numbers only become real numbers when they are written out in binary form using bits
    • Every natural number is a real number, since the reals include all natural, rational and irrational numbers

  18. The set {1.70, 1.90, 1.85} is put into ascending order of height in metres. What is the ordinal position of 1.90?

    • 3rd
    • 4th
    • 2nd
    • 1st

  19. In the well-ordered set S = {'a', 'b', 'c', 'd'}, what is the ordinal position of 'd'?

    • 5th
    • 4th
    • 3rd
    • 1st

  20. A sensor produces readings of 1.5 V. Which statement about the set needed for all possible voltages is correct?

    • Natural numbers are sufficient, since voltages are counted in whole units
    • Only rational numbers are needed, because irrational voltages cannot exist
    • Ordinal numbers are needed, since voltages are only ranked from smallest to largest
    • Real numbers are needed, since voltages can take any real value between two readings

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